Documentation/developer-guide.md

# Developer Guide

[TOC]

## Building

Gitiles requires [Bazel](https://bazel.build/) to build.

You need to use Java for building Gitiles. You can install Bazel from
bazel.build: https://bazel.build/versions/master/docs/install.html .
Alternatively, you can use `apt-get`.

```
$ sudo apt-get update
$ sudo apt-get install bazel
```

The best way to build and run gitiles is to use bazelisk.

```
$ go install github.com/bazelbuild/bazelisk@latest
$ export PATH=$PATH:$(go env GOPATH)/bin
```

Make sure to initialize and update the git submodules:
```
git submodule update --init
```

You are now ready to build and test.

```
$ bazelisk build //:gitiles
$ bazelisk test //...
```

## Troubleshooting

If you encounter build errors such as:

```
Error in execute: Argument 0 of execute is neither a path, label, nor string.
```

Make sure you have `python` available in your PATH. Since Debian 11 and Ubuntu
20.04 LTS (focal), there is no `/usr/bin/python` provided by default. You can
install a package to provide a link to Python 3:

```
sudo apt-get install python-is-python3
```

Upon uploading your new CL, if you encounter a message related to a
missing `Change-Id`, you are missing the commit hook. Likely the command
to download it should appear in the Hint section of the message. If it
does not, use the following command:

```
f=`git rev-parse --git-dir`/hooks/commit-msg ; mkdir -p $(dirname $f) ; curl -Lo $f https://gerrit-review.googlesource.com/tools/hooks/commit-msg ; chmod +x $f
```

## Running Locally and Testing

```
cd /path/to/repositories  # Don't run from the gitiles repo.
/path/to/gitiles/tools/run_dev.sh
```

This will recompile and start a development server.  Open
http://localhost:8080/ to view your local copy of gitiles, which
will serve any repositories under `/path/to/repositories`.

To run unit tests, refer to the aforementioned bazel test command.

## Pushing your changes
This repository does not work with `repo` tool. To push your CL to
staging, use the following command.

```
git push origin HEAD:refs/for/master
```


## Eclipse IDE

If you'd like to use Eclipse to edit Gitiles, first generate a project file:

```
tools/eclipse/project.sh
```

Import the project in Eclipse:

```
File -> Import -> Existing Projects into Workpace
```

The project only needs to be rebuilt if the source roots or third-party
libraries have changed. For best results, ensure the project is closed in
Eclipse before rebuilding.

## Running/Debugging from Eclipse IDE

Running Gitiles from Eclipse requires setting the
`com.google.gitiles.sourcePath` system property. The property value has to be
the root folder of the Gitiles source code, for example:

````
-Dcom.google.gitiles.sourcePath=/home/johndoe/git/gitiles
````

## Code Style

Java code in Gitiles follows the [Google Java Style Guide][java-style]
with a 100-column limit.

Code should be automatically formatted using [google-java-format][fmt]
prior to sending a code review.  There is currently no Eclipse
formatter, but the tool can be run from the command line:

```
java -jar /path/to/google-java-format.jar -i path/to/java/File.java
```

CSS in Gitiles follows the [SUIT CSS naming conventions][suit].

[java-style]: https://google.github.io/styleguide/javaguide.html
[fmt]: https://github.com/google/google-java-format
[suit]: https://github.com/suitcss/suit/blob/master/doc/naming-conventions.md

## Code Review

Gitiles uses Gerrit for code review:
https://gerrit-review.googlesource.com/

Gitiles uses the ["git push" workflow][1] with server
https://gerrit.googlesource.com/gitiles.  You will need a
[generated cookie][2].

[1]: https://gerrit-review.googlesource.com/Documentation/user-upload.html#_git_push
[2]: https://gerrit.googlesource.com/new-password

Gerrit depends on "Change-Id" annotations in your commit message.
If you try to push a commit without one, it will explain how to
install the proper git-hook:

```
curl -Lo `git rev-parse --git-dir`/hooks/commit-msg \
    https://gerrit-review.googlesource.com/tools/hooks/commit-msg
chmod +x `git rev-parse --git-dir`/hooks/commit-msg
```

Before you create your local commit (which you'll push to Gerrit)
you will need to set your email to match your Gerrit account:

```
git config --local --add user.email foo@bar.com
```

Normally you will create code reviews by pushing for master:

```
git push origin HEAD:refs/for/master
```

## Releases

Gitiles artifacts are published to the [gerrit-maven
bucket](http://gerrit-maven.storage.googleapis.com/). To release a new version,
you must have write access to this bucket. See
[Deploy Gerrit
Artifacts](https://gerrit-review.googlesource.com/Documentation/dev-release-deploy-config.html)
for PGP key setup and Google Cloud Storage access setup.

First, increment `GITILES_VERSION` in `version.bzl`, Gitiles uses
[Semantic Versioning](https://semver.org).
Get your change reviewed and submitted.

Then, run:

```
./tools/maven/mvn.sh deploy
```

Tag the release with a signed, annotated tag matching the version number, for
example "v0.4-1".

Once released, Maven projects can consume the new version as long as they point
at the proper repository URL. Similarly, Bazel projects using the `maven_jar`
bazlet can use the new version with `repository = GERRIT`.